Inlet manifold



D. GARDNER Aug. 2, 1949.

INLET MANIFOLD Filed March 26, 1945 D1713 dardner IN V ENTOR.

ATTORNEY.

Patented Aug. 2, 1949 UNITED STATES rATE T OFFICE INLET MANIFOLD Dale Gardner, Detroit, Mich, assignor to George M. Holley and Earl Holley Application March 26, 1945, Serial No. 584,802

1 Claim. 1

The object of this invention is to improve the distribution in an internal combustion engine having a downdraft carburetor and a horizontal inlet manifold. The problem with these engines is to insure that the fuel is divided uniformly between the different cylinders, especially at low engine speed with a wide-open throttle. The trouble is that the fuel is directed by the butterfly throttle to one side, and therefore the initial flow is directed to one side or the other of the lateral passages of the inlet manifold. If the butterfly throttle is arranged with its shaft in line with the cylinders, the connection of the throttle to the foot accelerator becomes complicated. It is to correct this tendency to unequal distribution of the fuel between these lateral passages that this invention is made.

The figure shows diagrammatically the preferred form of my invention.

In the figure, a float chamber A supplies fuel to a nozzle 33, which discharges into a venturi C, against a butterfly throttle D. E is a mixture outlet leading to an inlet manifold F, G is a spring-loaded, mushroom-type valve subject to the impact of the mixture flowing down past the throttle D. At idle, the valve G rises to the upper position shown in broken lines. At high engine speed, with the throttle valve D wide open, the valve G is pushed down to the lower position shown in broken lines.

At low engine speed, wide open throttle, the valve G assumes the position shown in the drawing in full lines. At low engine speed, wide open throttle, distribution is apt to be quite poor, and I have discovered that the restriction at this portion of the manifold has beneficial results.

in order that the valve G shall not obstruct the flow at maximum speed, it is necessary for the valve G to be responsive to the impact of the fuel and air flow past the throttle D. Hence, a flexible spring is provided to support the valve G.

Operation When idling, the valve G assumes the upper of the three positions shown, and the mixture discharged by the throttle D strikes the top of the mushroom valve G, and liquid fuel is spread around the periphery of the valve by the air flow. The liquid fuel deposited on the top of the valve G is then reatomized and uniformly distributed between the two branches of the inlet manifold F by the air stream which strikes the valve G. When the throttle D opens, more and more fuel is discharged through the nozzle B and more and more air is discharged through the venturi C. The impact of this fuel and air flowing through the mixture outlet D upon the mushroom valve G pushes this spring-loaded valve down to the position shown in the drawing in full lines, and liquid fuel is spread upon the top surface of the mushroom valve G and distributed equally between the two branches of the inlet manifold F by air flowing into the engine.

At high speed with the throttle D wide open, the impact on the valve G is so great that the valve G is pushed right down out of the way and has little or no influence on the operation of the engine, the spring supporting the valve G being sufficiently flexible to yield.

At high speed and at wide open throttle, distribution is not too bad, and in any event, it is at low engine speed that trouble is experienced and expected.

The valve G occupies the central position between the two arms of the manifold F in which there is normally no definite direction of flow, but a mere pulsating flow. It is here where a portion of the fuel is deposited and where it accumulates until it drains into the engine in such a large charge as to seriously disturb the mixture ratio and thus cause rough running.

The space occupied by the disc valve G is, in the ordinary manifold, a dead air space in which fuel is automatically deposited. The disc valve G thus maintains the velocit of flow at the critical zone where the air flow turns to the left or right. As a result, any liquid fuel deposited on the bottom of the inlet manifold F is deposited near one of the outlets leading to the inlet valve of the engine. The restriction in filling the engine with air is so small that it can hardly be measured in inches of water.

What I claim is:

An inlet manifold for an internal combustion engine having a downwardly inclined mixture entrance to said manifold, said. manifold having lateral passages and mixture entrance controlled by a throttle valve, a disc valve located in said manifold downstream from the intersection of the mixture entrance with the said lateral passages and axially of said mixture entrance, a spring engaging with and supporting said valve in a closed position so as to move said valve into a position to throttle the inflowing mixture entering the manifold as the engine comes to rest and to yield so as to permit said valve to be moved by the inflowing mixture into an unthrottling position when the throttle valve in the mixture entrance is opened and when the engine load permits the engine speed to increase.

DALE GARDNER.

(References on following page) REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Kemp May 2'7, 1919 Aseltine Sept. 3, 1929 Number 

